1. Field of the Invention
The present invention relates to a pattern forming method, a method for manufacturing an electronic device, and an electronic device. More specifically, the present invention relates to a pattern forming method which is suitable for a process for manufacturing a semiconductor such as an IC, a process for manufacturing a circuit board for a liquid crystal, a thermal head, or the like, and other lithographic processes for photofabrication, a method for manufacturing an electronic device, and an electronic device.
2. Description of the Related Art
Since a resist for a KrF excimer laser (248 nm) was developed, a pattern forming method using chemical amplification has been used in order to complement desensitization caused by light absorption. For example, in a positive tone chemical amplification, a photoacid generator included in an exposed area first decomposes by irradiation with light to generate an acid. Further, during a post exposure bake (PEB) process or the like, an alkali-insoluble group included in a photosensitive composition is changed to an alkali-soluble group by the catalytic action of an acid thus generated. Thereafter, development is carried out by using, for example, an alkaline solution. Thus, the exposed area is removed to obtain a desired pattern.
In the method, various alkaline developers have been suggested as the alkaline developer. For example, a water-based alkaline developer with 2.38% by mass of tetramethylammonium hydroxide (aqueous TMAH solution) is universally used as the alkaline developer.
Moreover, in order to make semiconductor elements finer, the wavelength of a light source for exposure has been shortened and a projection lens with a high numerical aperture (high NA) has been advanced. Currently, an exposure machine using an ArF excimer laser having a wavelength of 193 nm as a light source has been developed. As a technique for further improving resolving power, a method (that is, a liquid immersion method) in which a liquid having a high refractive index (hereinafter also referred to as an “immersion liquid”) is charged between a projection lens and a sample has been proposed. In addition, EUV lithography in which exposure is carried out with ultraviolet rays at a shorter wavelength (13.5 nm) has also been proposed.
Moreover, recently, a pattern forming method using a developer (organic developer) including an organic solvent has also been developed (see, for example, JP2011-123469A and WO2011/122336A). For example, JP2011-123469A and WO2011/122336A each disclose a pattern forming method including a step of coating a substrate with a resist composition whose solubility in an organic developer is reduced upon irradiation with active light or radiation, an exposing step, and a step of carrying out development using an organic developer. It is considered that according to these methods, it is possible to stably form a fine pattern with high accuracy.
In addition, JP2013-174715A discloses a pattern forming method including forming a film using a resist composition including a resin having a phenolic hydroxyl group, tetrabutylammonium hydroxide, and carrying out development with an organic developer.